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Comparative Genomics

We study comparisons of the genomes of distantly related mammals and other vertebrates. We specialise in Australian mammals.

Marsupials (e.g. kangaroos, wallabies) and monotremes (e.g. platypus) are the mammals most distantly related to humans, so we can use comparisons of their DNA sequences and gene arrangements.

To explore the organisation, function and evolution of the human genome. We are particularly interested in how sex (maleness or femaleness) is determined in mammals. We are also comparing genomes of birds and reptiles with those of mammals.

We are also using a comparative strategy to explore the mechanism and evolution of complex gene regulatory circuits like X chromosome inactivation and genomic imprinting. We aim to determine how these systems work and also why they evolved.

Current Research

Genome organisation and evolution

We use "chromosome painting" to see how chromosomes have changed during evolution. The same genome regions are arranged and rearranged in chromosomes like pieces of a jigsaw puzzle. We study how chromosomes are organised in the nucleus of somatic cells and sperm and apply this to suggest how position affects activity.

Kangaroo Genomics

With the formation of the ARC Centre for Kangaroo Genomics (KanGO), we will be characterising the X chromosome and an autosome by genetic and physical mapping, then ordering and contigging BAC clones along their length. Ultimately, we hope to completely sequence this part of the genome.

Sex determination and spermatogenesis

Mammals determine sex by means of the SRY gene on the Y chromosome, which triggers testis differentiation. We are investigating how this gene evolved from an original brain determining gene on the X chromosome. We are also studying other genes in the sex determining pathway, as well as genes on the Y chromosome required for male fertility. We are looking at sex determination in reptiles, particularly those that indulge in both temperature and genetic sex determination.

Sex chromosome evolution

The Y chromosome is interesting because it contains few genes and lots of junk DNA. We are studying homologues of human Y chromosome genes to investigate how some genes can acquire new functions while others are degraded and lost during evolution. The X chromosome is also unusual because it is present in one copy in males and two in females and seems to have a high concentration of genes involved in sex and reproduction, as well as intelligence genes. Sex chromosomes of birds and snakes are quite different in gene content, but have many parallels.

Epigenetic control of gene activity

The X chromosome is present in one copy in XY males and two in XX females, but one copy is inactivated in females. We are investigating how the locus XIST controls the process of transcriptional repression. In particular we are studying the evolution and function of XIST in kangaroos, where X inactivation is partial and only affects the father's X chromosome, and discovering the mode of dosage compensation in the platypus.